Growing up an a hobby farm with 20-40 (depending on the time of year), this is my experience too. Lambs are playful and full of spunk, but as they grow older they quickly become full-time grazing machines. Rams are just vicious.
Classic HN here that no matter how obscure the topic, we have posts from 3 different people with real world experience.
My favorite was the person who happened to be burning a boat for fuel when it was being debated whether a crew could survive a shipwreck for years by using the ship as a fuel source. https://news.ycombinator.com/item?id=10803552
I'm not sure that sheep-farming is particularly obscure.
I imagine it is among IT people, who are the prime audience for HN.
Also, it wasn't just sheep farming. It was treating the lambs as pets.
Aggressive rams are partially a byproduct of testosterone and selective breeding, some small scale farmers will leave rams in with ewes and their newborns to protect them from predators.